On Feb. 9, 1988, U.S. Pat. No. 4,724,400, entitled "Linear Amplifier Assembly" was issued in the name of G. G. Luettgenau to TRW Inc. (the "400 patent"). Such patent is treated herein solely as a publication. The disclosure of the '400 patent as a publication is, however incorporated herein by reference and made a part hereof.
The '400 patent shows and describes a microwave splitter-combiner apparatus comprising a cylindrical stack of vertically superposed circular metallic plates defining within the stack an upper splitter waveguide and a lower combiner waveguide. Each such waveguide comprises a pair of vertically spaced metallic walls and a chamber between and bounded by such walls and providing a passage through which microwaves propagate, the chamber being essentially in the form of a horizontal cylindrical disc. In the splitter waveguide, the microwaves travel through its cylindrical disc chamber from its center radially outward while, in the combiner waveguide, such travel in its chamber is radially inward towards the center of the chamber.
Disposed on a plate member providing a top closure for the mentioned stack is a set of twenty r.f. amplifier operating units each essentially in the shape of a rectangular block. The twenty units are equiangularly spaced in carousel fashion around the top of such member in respective radial planes which are vertical and pass through the vertical axis of the stack.
Each of such twenty r.f. amplifier units is coupled to the splitter waveguide by an input coaxial connector and to the combiner waveguide by an output coaxial connector. In the operation of the apparatus, high frequency electromagnetic energy is fed to the splitter waveguide's center, travels therefrom radially outward through the waveguide's chamber to the twenty input connectors and is then fed upward by them to the twenty amplifiers which operate in parallel to amplify such energy. The amplified energy is then fed via the twenty output connectors to points in the combiner waveguide's chamber which are radially outward of the chamber's center. From those points the energy travels as waves radially inward through the chamber to its center to there be combined and provide an amplified output from the apparatus.
In the apparatus of the '400 patent, the input microwave energy is supplied to a splitter cavity via an input coupling unit described in that patent as a coaxial type connector and the amplified microwave energy is tapped off from the combiner cavity by another similarly described coupling unit. Both such connectors are best depicted in FIG. 5a of the patent, and the center conductor of each of such type connectors is shown in that figure as being of constant diameter and having its front received in a constant diameter hole formed in one of the metallic cavity-bounding plates.
Beyond stating that the center conductor of the output connector touches and makes electrical contact with the metallic plate providing the hole in which that conductor is received, the '400 patent does not disclose any of the details of how electrical contact is made in the apparatus shown thereby between the center conductors of the input and output connectors and the metallic plates in which such conductors are received. The inventor knows, however, how such electrical contacts were made in accordance with the practice of the prior art as represented by the '400 patent.
Specifically, the front end of the center conductor of each connector was received in a hole formed in the receptacle plate and of greater diameter than the conductor. An electroconductive epoxy resin was then introduced in the hole into the interstice between the conductor and the hole wall. The epoxy was then cured by heating the entire apparatus in an oven. Such procedure had the disadvantages, however, that proper curing of the epoxy required about an hour of heating and that, all during such heating, care had to be taken to maintain the proper alignment of the conductor relative to the hole.